#origin ⇒ String

The source of the CMK's key material. When this value is AWS_KMS,
AWS KMS created the key material. When this value is EXTERNAL, the
key material was imported from your existing key management
infrastructure or the CMK lacks key material.

#valid_to ⇒ Time

The time at which the imported key material expires. When the key
material expires, AWS KMS deletes the key material and the CMK
becomes unusable. This value is present only for CMKs whose Origin
is EXTERNAL and whose ExpirationModel is KEY_MATERIAL_EXPIRES,
otherwise this value is omitted.